Abstract

Atomic force microscopy and Raman spectroscopy were used to investigate the development of the surface morphology and ordering of and A series of lattice-matched highly ordered and samples ranging in thickness from 2 to 50 nm were grown by low-pressure metalorganic vapor phase epitaxy on (001) direct and vicinal substrates. Raman spectroscopy provided direct evidence of -type ordering in layers as thin as 10 nm for and 5 nm for We find that the morphology of both and on (001)6B substrates consists of ridges with heights ranging from 2 to 10 nm, which are aligned predominately along the [110] direction. For growth on (001) direct substrates, ridges similar to those obtained on 6B vicinal substrates form with no preferential orientation, while growth on (001) direct substrates proceeds by a combination of two-dimensional-island and step-flow growth. The average roughness of the GaInP layers is approximately twice that of GaInAs layers. These findings suggest it may be difficult to produce abrupt large-area heterointerfaces in structures containing ordered and alloys.